Hinge cap
The hinge cap design with specific notches and connecting portions addresses the challenge of separating high-modulus resin hinge caps from containers, ensuring secure sealing and easy detachment, thus preventing leakage and facilitating repeated use.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- YOSHINO KOGYOSHO CO LTD
- Filing Date
- 2024-11-29
- Publication Date
- 2026-06-10
AI Technical Summary
Hinge caps made from resins with a flexural modulus of 280 MPa or higher face difficulty in starting the separation cut when separating from containers, especially when containing liquids like limonene, leading to potential leakage and fit issues.
A hinge cap design featuring a cap body with an outer peripheral notch, inner peripheral notch, slit groove, and connecting portions that facilitate easy separation, using resins like polyethylene or polypropylene with a flexural modulus of 280 MPa or higher, ensuring secure fitting and easy detachment.
The design allows for secure sealing and easy separation of the hinge cap from the container, maintaining integrity even with high-modulus resins, preventing leakage and facilitating repeated use.
Smart Images

Figure 2026095274000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a hinge cap fitted to the mouth of a container, and more particularly to a hinge cap that can be easily separated from the container even when a resin having a flexural modulus of 280 MPa or more is used as the material.
Background Art
[0002] Conventionally, there is known a hinge cap provided with a separation mechanism for separating the cap body from the container by pulling up the opened upper lid at the time of disposal. In this type of hinge cap, various structures for breaking the outer peripheral wall portion fitted to the mouth of the container have been proposed. However, due to the balance with the strength and sealing property for fitting and holding on the mouth of the container, a considerably large force is required when breaking the outer peripheral wall portion.
[0003] In order to cope with this, the cap body is provided with a mounting portion including an outer peripheral wall portion and an inner cylinder vertically provided with the fitting portion with the mouth of the container interposed therebetween, and a base wall portion that is connected to the outer peripheral wall portion and the inner cylinder and has an engaging portion with the upper lid at the upper part. The outer peripheral wall portion connected to the hinge is provided with a vertical tear line provided with a cut portion in the vertical direction in the vicinity of the hinge. Between the outer peripheral wall portion and the base wall portion, a slit groove having an upward opening over an arc range of a predetermined circumferential angle from the vertical tear line is provided. On the bottom surface of the slit groove, a circumferential tear line composed of a thin connecting portion connecting the outer peripheral wall portion and the base wall portion is provided connected to the vertical tear line. A hinge cap is known (see, for example, Patent Document 1).
[0004] In addition, for a hinge cap provided with a separation mechanism for food, polyethylene (PE) is mainly used as the material in order to facilitate breaking the separation start portion of the cap body at the time of separation. However, for example, when a liquid containing limonene is contained, polyethylene with a flexural modulus of less than 270 MPa reacts with the liquid, causing the polyethylene, which is the material of the hinge cap, to soften. This results in dimensional errors and a weaker fit with the mouth of the container, potentially leading to a decrease in rotational torque and leakage. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] Japanese Patent Publication No. 2012-153429 [Overview of the project] [Problems that the invention aims to solve]
[0006] Therefore, for hinge caps equipped with a separation mechanism, resins with a flexural modulus of 280 MPa or higher (for example, polyethylene or polypropylene (PP)) are suitable as materials that have minimal impact when containing a liquid containing limonene. However, when using a resin with a bending modulus of 280 MPa or higher as the material for the hinge cap with a separation mechanism, there was a problem in that the starting point of the separation cut became difficult to break when separating from the container.
[0007] The present invention aims to solve the above problems and to provide a hinge cap with a separation mechanism that, even when a resin with a bending modulus of elasticity of 280 MPa or higher is used as the material for the hinge cap, allows the separation cutting start portion to be easily broken when separating from the container. [Means for solving the problem]
[0008] To solve the above problems, the present invention provides a hinge cap comprising a cap body fitted to the mouth of a container and a lid attached to the cap body via a hinge, wherein the cap body has a partition wall that abuts against the upper surface of the mouth of the container and seals the opening, and an outer peripheral wall portion that extends vertically from the outer edge of the partition wall, the outer peripheral wall portion has an outer peripheral notch cut vertically from the outer peripheral surface near the hinge, an inner peripheral notch cut vertically on the inner peripheral surface corresponding to the outer peripheral notch, and a slit groove recessed on the upper surface over a predetermined arc range in the circumferential direction from the hinge side of the outer peripheral notch, the slit groove has a circumferential cut portion on the inside of the bottom surface that starts from the upper end of the inner peripheral notch, and the outer peripheral notch has an upper connecting portion that is detachably connected at a height corresponding to the bottom surface of the slit groove, a bottom connecting portion that is detachably connected at the lower end, and a window portion that penetrates between the upper connecting portion and the bottom connecting portion.
[0009] As an embodiment of the hinge cap, the upper connecting portion is formed inside the outer peripheral cutout, and the bottom connecting portion is formed outside the outer peripheral cutout. Furthermore, the outer surface of the upper connecting portion and the inner surface of the bottom connecting portion are formed on a virtual extension plane. The material is polyethylene with a flexural modulus of 280 MPa or higher, and the material is polypropylene with a flexural modulus of 500 MPa or higher. [Effects of the Invention]
[0010] By adopting the above configuration, the hinge cap of the present invention can be formed from a resin that has little effect on the liquid contents containing limonene, has a flexural modulus of 280 MPa or higher, can be securely fitted to a container when sealed, and can be easily separated from the container when discarded. [Brief explanation of the drawing]
[0011] [Figure 1] This is a side cross-sectional view showing the closed state of a container fitted with a hinged cap, which is an embodiment of the present invention. [Figure 2] This figure shows the open state of a hinge cap, which is an embodiment of the present invention; (a) is a top view and (b) is a side cross-sectional view. [Figure 3] This is an enlarged view of the main part of a hinge cap, which is an embodiment of the present invention, where (a) is an enlarged view of the main part of Figure 2(a), and (b) is a cross-sectional view taken along the line XX in (a). [Figure 4] This is a top view showing the intermediate process of separating a hinge cap from a container fitted with a hinge cap, which is an embodiment of the present invention. [Modes for carrying out the invention]
[0012] Next, the hinge cap of the present invention will be described with reference to the drawings showing embodiments. In the following explanation, as seen in Figure 1, the left direction will be referred to as the "dispensing side," the right direction as the "back side," the upward direction as "up," and the downward direction as "down."
[0013] (Examples) In Figure 1, A is a container, B is a cap body fitted onto container A, and D is a lid that is attached to cap body B via hinge C so as to be openable and closable. In this embodiment, a hinged cap E comprising cap body B, hinge C, and lid D is fitted onto container A by pressing it into place.
[0014] The hinge cap E of the present invention uses a resin as its material that is less affected by the presence of a liquid containing limonene and has a flexural modulus of 280 MPa or higher, such as polyethylene or polypropylene. When using polyethylene with a flexural modulus of 280 MPa or higher, it is preferable to use a blend of polyethylene with a low flexural modulus and polyethylene with a high flexural modulus, rather than using polyethylene alone. For use in this embodiment, for example, Sun Allomer Co., Ltd.'s PM940M (random copolymer, flexural modulus of 550 MPa) is preferred as the polypropylene. In addition, polypropylene is not particularly limited as long as it is a random copolymer.
[0015] Container A has a mouth part 1 at the upper part, and a fitting ridge 2 is provided on the upper part of the outer peripheral surface of the mouth part 1. As shown in FIGS. 1 and 2, the cap body B includes a partition wall 5 that abuts on the upper end surface of the mouth part 1 of the container A and seals the opening, a pouring outlet 5a that penetrates a position on the pouring-out side from the center of the partition wall 5, a pouring-out cylinder 6 erected from around the pouring outlet 5a, an annular lid engaging part 7 formed on the outer edge of the upper surface of the partition wall 5 and engaging with the lid body D, an inner cylinder 8 vertically provided from the lower surface of the partition wall 5 and whose outer periphery is inserted into the inner periphery of the mouth part 1, and an outer peripheral wall part 9 vertically provided from the outer edge of the partition wall 5. The outer peripheral wall part 9 is provided with an engaging protrusion 10 that engages with the fitting ridge 2 of the mouth part 1 of the container A at the lower part of the inner periphery. In this embodiment, a rectifying part 12 is vertically provided from the periphery of the pouring outlet 5a on the lower surface of the partition wall 5.
[0016] The lid engaging part 7 has an arc-shaped lid engaging protrusion 15 erected with a notch part 14 where the upper surface of the partition wall 5 is cut from the center on the back side to both sides within a predetermined range remaining, and within the notch part 14, a back side protrusion 16 is erected at the same height as the lid engaging protrusion 15 with a gap 14a left from both ends of the lid engaging protrusion 15, and a locking ridge 17 is provided on the outer periphery of the lid engaging protrusion 15.
[0017] At the upper part of the outer peripheral wall part 9, on the pouring-out side, a stepped concave part 19 is recessed from the outer periphery with a predetermined depth in an arc shape within an arc range of approximately 180°, and the remaining back side has the upper surface at the same height as the upper surface on the pouring-out side of the partition wall 5, and a hinge C is continuously provided at the upper end of the outer periphery.
[0018] As shown in FIGS. 2(a) and 3, on the back side of the outer peripheral wall portion 9, from the outer peripheral surface located near either the left or right side of the hinge C (in the embodiment, the left side) to the end face 20a on the hinge C side, the end face 20b on the side opposite to the hinge C, and the corner portion 20c connecting the inner ends of the end face 20a and the end face 20b, the outer peripheral cut portion 20 cut in a V shape in plan view is cut from the upper surface of the outer peripheral wall portion 9. On the inner peripheral side of the outer peripheral wall portion 9 corresponding to the outer peripheral cut portion 20, the inner peripheral cut portion 21 cut at a height α (the lower end face 22a of the upper connecting portion 22) from the lower end is cut including the engaging projection 10. In the outer peripheral cut portion 20, an upper connecting portion 22 formed of a breakable thin wall and connecting the end face 20a and the end face 20b is disposed inside near the height α of the corner portion 20c (the height corresponding to the bottom surface 25a of the slit groove 25), and a bottom connecting portion 23 formed of a breakable thin wall and connecting the end face 20a and the end face 20b is disposed outside the lower end portion. The outer peripheral cut portion 20 is connected in a bridge shape by the upper connecting portion 22 and the bottom connecting portion 23 as a separation starting portion. Furthermore, between the lower end face 22a of the upper connecting portion 22 and the upper end face 23a of the bottom connecting portion 23 of the corner portion 20c, a window portion 24 penetrating the inside and outside of the outer peripheral wall portion 9 is formed. As shown in FIG. 3(b), the outer side surface 22b of the upper connecting portion 22 and the inner side surface 23b of the bottom connecting portion 23 are formed on the virtual extension plane β, which makes it easier to mold.
[0019] On the hinge C side of the outer peripheral cut portion 20 on the back side of the outer peripheral wall portion 9, as shown in FIGS. 2(a) and 3(a), starting from a position separated by the upper vertical slit 28 adjacent to the inner peripheral side of the end face 20a, the slit groove 25 is recessed on the upper surface so as to extend in the circumferential direction (along the hinge C side) to the end of the stepped concave portion 19. On the side opposite to the hinge C of the outer peripheral cut portion 20 of the outer peripheral wall portion 9, it is the thick portion 26 from the end face 20b to the end of the stepped concave portion 19. Note that the vertical slit 28 may be a thin wall portion or a weakened portion. The depth of the slit groove 25 is recessed to a depth near the upper end of the upper connecting portion 22, at least near the starting point on the end face 20a side, and the rest of the groove is recessed in a manner that gradually increases in height, continuing to the height of the end of the stepped recess 19. Starting near the upper end of the upper connecting portion 22 adjacent to the vertical slit 28, a circumferential cut portion 29a, formed by cutting a thin circumferential connecting portion 29 that connects the outer peripheral wall portion 9 and the partition wall 5, extends in an arc shape to the center of the back side on the inner circumference side of the bottom surface 25a of the slit groove 25. Furthermore, the portion of the outer peripheral wall portion 9 that is outside the slit groove 25 on the back side becomes the back outer wall portion 27, and a hinge C is connected to a predetermined position at the upper end of the outer periphery of the back outer wall portion 27.
[0020] As shown in Figures 1 and 2, the lid D is rotatably attached to the upper outer edge of the outer peripheral wall portion 9 of the cap body B via a hinge C, and is provided with a top wall 30, a side peripheral wall 31 that extends vertically from the periphery of the top wall 30 and has a hinge C connected to its lower end on the rear side, and a sealing cylinder 32 that extends vertically from the inner surface of the top wall 30 and seals the dispensing cylinder 6. A thin-walled portion 33, which can be deformed along the outer circumference of the sealing cylinder 32, is recessed on the lower surface of the top wall 30.
[0021] The inner circumference of the lower end of the side circumferential wall 31 is provided with an engaging recess 35 that engages with the lid engaging projection 15 of the lid engaging portion 7 to maintain the closed lid state. The engaging recess 35 has a locking portion 36 on its inward-facing surface that engages with the locking projection 17 of the lid engaging projection 15, and its downward-facing surface 35a is in contact with the upper surfaces of the lid engaging projection 15 and the rear-side projection 16. In this embodiment, the downward-facing surface 35a of the engaging recess 35 is in contact with the upper surface of the rear side projection 16, but it is not necessary for them to be in contact; they may be in close proximity. Furthermore, multiple locking protrusions 37 are provided at intervals in the circumferential direction, inside the engaging recess 35 of the side circumferential wall 31, except for the area opposite the rear side projection 16. These protrusions contact the upper inner circumference of the lid engaging projection 15 when the lid is closed, thereby suppressing the outward spreading of the side circumferential wall 31.
[0022] On the dispensing-side outer edge of the lower surface of the side circumferential wall 31, an arc-shaped covering wall 38 is provided so as to cover the stepped recess 19 of the outer circumferential wall portion 9 of the cap body B when the lid is closed, with its lower end approaching or contacting the recessed surface of the stepped recess 19. A knob 39 is formed on the lower outer circumference of the covering wall 38 on the dispensing side.
[0023] In this embodiment, to prevent unauthorized opening before use, a shrink label, sealing member, or the like may be provided between the cap body B and the lid D, although this is not shown in the illustration.
[0024] Next, the usage and effects of this embodiment will be described. In this embodiment, the hinged cap E is initially integrally molded in the open state shown in Figure 2. The lid D is then rotated via the hinge C and placed over the cap body B, and the cap is closed as shown in Figure 1. At that time, the lower outer surface of the sealing cylinder 32 of the lid D is in close contact with the lower inner surface of the dispensing cylinder 6 of the cap body B, thus sealing it. Furthermore, the engaging recess 35 of the side peripheral wall 31 of the lid D engages with the lid engaging projection 15 of the lid engaging portion 7 of the cap body B, thereby maintaining the lid closed.
[0025] In this embodiment, when performing a leak test of the seal between the dispensing tube 6 of the cap body B and the sealing tube 32 of the lid D after closing the hinge cap E, air is blown from below toward the dispensing port 5a of the cap body B. If there is a defect in the seal between the dispensing tube 6 of the cap body B and the sealing tube 32 of the lid D, the air leaking outward from the dispensing tube 6 flows out through the gap 14a of the notch 14, which is excluding the rear side projection 16 of the cap body B that abuts against the downward surface 35a of the engaging recess 35 of the lid D. The air then escapes out between the inward surface of the engaging recess 35 and the gap 14a and the outside of the rear side projection 16, thus allowing for the detection of a seal defect.
[0026] Next, as shown in Figure 1, the closed hinge cap E is pressed and fitted onto the opening 1 of container A, which is filled with the liquid. In the capping process, the opening 1 of container A is placed against the annular groove formed between the inner cylinder 8 and the outer peripheral wall 9 of the cap body B, and pressing force is applied from above the lid D, causing the engaging projection 10 of the outer peripheral wall 9 to overcome the fitting projection 2 of the opening 1 and engage, thereby fitting the opening 1 of container A by being sandwiched between the outer circumference of the inner cylinder 8, the inner circumference of the outer peripheral wall 9, and the lower outer edge surface of the partition wall 5.
[0027] In this embodiment, the hinge cap E has a thin-walled upper connecting portion 22 and a bottom connecting portion 23 that are connected in a bridge-like manner, making it easily deformable. Therefore, even if polyethylene or polypropylene is used as the resin with a bending modulus of elasticity of 280 MPa or more, the starting point for separation and cutting will not break when the cap is installed.
[0028] Furthermore, when the cap is pressed in, the downward-facing surface 35a of the engaging recess 35 of the lid D abuts against the upper surface of the lid engaging projection 15 and the upper surface of the rear side projection 16 of the cap body B. In addition, the locking projection 37, which is provided inside the engaging recess 35, abuts against the upper inner circumference of the lid engaging projection 15 and catches, thereby suppressing the outward spreading of the side circumferential wall 31 in response to the pressing force from above the lid D. In particular, on the hinge C side of the lid D, the outward spreading of the side peripheral wall 31 is suppressed by the hinge C, and the downward surface 35a of the lid D abuts against the upper surface of the rear side projection 16 of the cap body B, thereby suppressing deformation due to downward pressure.
[0029] In this embodiment, when the hinge cap E is sealed into a container A filled with liquid at high temperature, the pressure inside the container A increases. However, since the top wall 30 has a deformable thin-walled portion 33 on the outside of the sealing cylinder 32, only the inner circumference of the thin-walled portion 33 rises, releasing the pressure outwards from the dispensing cylinder 6. This prevents interference between the engagement recess 35 of the side circumferential wall 31 of the lid D and the lid engagement portion 7 of the cap body B, and the lid remains closed. Therefore, even if the liquid inside is at a high temperature, it is possible to prevent the lid D from opening due to increased internal pressure. Furthermore, when the lid is closed and the container is dropped upside down, even if an impact force is applied to the top wall 30 of the lid D, the thin-walled portion 33 absorbs the impact received by the lid D, preventing the sealing cylinder 32 from being pushed in or pulled away from the dispensing cylinder 6. This does not affect the tight seal between the sealing cylinder 32 and the dispensing cylinder 6 of the cap body B, preventing the sealing cylinder 32 and the dispensing cylinder 6 from coming undone or damaging each other.
[0030] When using the liquid contents of container A, lifting the lid D by placing your fingers on the tab 39 releases the seal between the sealing cylinder 32 of lid D and the dispensing cylinder 6 of cap body B, and also releases the engagement between the side circumferential wall 31 of lid D and the lid engaging portion 7 of cap body B, allowing lid D to be opened. When container A is tilted towards the dispensing side, the liquid contents of container A are straightened by the flow straightening portion 12 on the lower surface of the partition wall 5 of cap body B and can be dispensed through the dispensing port 5a and the dispensing cylinder 6.
[0031] After dispensing the liquid contents, return container A to an upright position and close lid D on cap body B again. This causes the sealing cylinder 32 of lid D to tightly adhere to the inner circumference of the dispensing cylinder 6 of cap body B, forming a seal and sealing the inside of container A. The hinge cap E can then be used repeatedly by opening and closing lid D.
[0032] In this embodiment, the hinged cap E is provided with a covering wall 38 on the dispensing-side outer edge of the lower surface of the side peripheral wall 31 of the lid D. This hides the stepped recess 19 of the outer peripheral wall portion 9 of the cap body B when the lid is closed, and also prevents fingers placed under the knob portion 39 from bumping into the inside of the lid D when opening, thus keeping the inside of the cap clean.
[0033] Next, we will describe a method for separately disposing of the hinge cap E after all the liquid contents in container A have been used. In this process, the lid D of the hinge cap E is opened, and the lid D is grasped with the fingers and pulled outward. This pulls the rear outer wall portion 27, which is connected to the hinge C of the outer periphery wall portion 9 via the hinge C, pulling the rear side of the connected outer periphery wall portion 9 and deforming it from above. The outer perimeter cutout 20 is pulled from above by the pulling force on the back side of the outer perimeter wall 9. When the outer perimeter cutout 20 is pulled, the upper connecting portion 22 and the bottom connecting portion 23 that connect the outer perimeter cutout 20 are spread out to the sides. Then, force is applied to the upper connecting portion 22 of the outer peripheral cut portion 20, causing it to break. Since the force is applied from the upper connecting portion 22, the force acts as the starting point for the fracture of the outer peripheral cut portion 20, causing it to break easily, and finally each portion breaks completely.
[0034] When the lid D is pulled further, the circumferentially cut portion 29a, from the end face 20a connected to the inner circumferential notch 21, separates in the circumferential direction from the end face 20a side, where the slit groove 25 has been cut out. After the separation of the circumferential cut portion 29a is complete, as the fracture progresses, as shown in Figure 4, a portion of the fractured outer peripheral wall 9 of the lid D and the cap body B connected to it separates from the cap body B. When the outer peripheral wall portion 9 of the broken part of the cap body B connected to the lid D is pulled, the engagement between the engaging projection 10 of the outer peripheral wall portion 9 and the fitting projection 2 of the mouth portion 1 of container A is released, and when pulled upwards, the hinge cap E can be easily removed from container A and disposed of separately.
[0035] In this embodiment, the hinge cap E has an outer circumference notch 20 and an inner circumference notch 21 on the back side of the outer circumference wall 9 of the cap body B. The outer circumference notch 20 is connected by an upper connecting portion 22 and a bottom connecting portion 23. The space between the lower end surface 22a of the upper connecting portion 22 and the upper end surface 23a of the bottom connecting portion 23 is a window portion 24 that penetrates both the inside and outside of the outer circumference wall 9. Therefore, even if the hinge cap E is made of polyethylene or polypropylene, which are resins that have little effect on the liquid contents containing limonene and have a flexural modulus of 280 MPa or higher, the upper connecting portion 22 and the bottom connecting portion 23 are easily deformed when the cap is sealed into the container A, so it can be fitted without breaking. Furthermore, when separating and disposing of the cap from the container A, a part of the outer circumference wall 9 can be easily broken and the hinge cap E can be removed. [Industrial applicability]
[0036] The hinge cap of the present invention is suitable as a hinge cap for containers that hold food, etc., because, even when made of a resin that has little effect on the contents containing limonene and has a flexural modulus of 280 MPa or higher, it can be securely fitted to a container by being pressed into it, and can be easily separated from the container when discarded. [Explanation of symbols]
[0037] A container B Cap Body C Hinge D Lid body E Hinge Cap α height β virtual extension surface 1 Mouth 2. Interlocking protrusions 5 Bulkhead 5a spout 6 Pour tube 7 Lid engagement part 8 Inner cylinder 9 Outer wall 10 Engagement protrusion 12 Rectifier 14 Notch 14a Gap 15 Lid engaging protrusion 16 Rear protrusion 17 Locking protrusion 19 recessed steps 20 Outer circumference cut section 20a end face 20b End surface 20c corner 21 Inner circumference cut section 22 Upper connection part 22a Lower end surface 22b External surface 23 Bottom connection part 23a Upper end surface 23b Inside surface 24 Window section 25 Slit grooves 25a Bottom 26 Thick part 27 Rear outer wall 28 vertical slits 29 Circumferential connection 29a Circumferential cut section 30 Top Wall 31 Side wall 32 Closed Envelope 33 Thin-walled section 35 Engaging recess 35a Downward surface 36 Locking part 37 Locking convex piece 38 Covered wall 39. Thumb part
Claims
1. A hinged cap comprising a cap body fitted onto the mouth of a container, and a lid body attached to the cap body via a hinge, The cap body has a partition that abuts against the upper surface of the mouth of the container and seals the opening, and an outer peripheral wall portion that extends downward from the outer edge of the partition. The outer periphery wall portion has an outer periphery notch cut vertically from the outer periphery surface near the hinge, an inner periphery notch cut vertically from the inner periphery surface corresponding to the outer periphery notch, and a slit groove recessed on the upper surface over a predetermined arc range in the circumferential direction from the hinge side of the outer periphery notch. The slit groove has a circumferential cut portion on the inside of the bottom surface, starting from the upper end of the inner circumferential cut portion. A hinge cap characterized in that the outer periphery cutout has an upper connecting portion that connects detachably at a height corresponding to the bottom surface of the slit groove, a bottom connecting portion that connects detachably at the lower end, and a window portion that penetrates between the upper connecting portion and the bottom connecting portion.
2. The upper connecting portion is formed inside the outer periphery cutout, The hinge cap according to claim 1, characterized in that the bottom connecting portion is formed on the outside of the outer peripheral cutout portion.
3. The hinge cap according to claim 2, characterized in that the outer surface of the upper connecting portion and the inner surface of the bottom connecting portion are formed on a virtual extension plane.
4. The hinge cap according to any one of claims 1 to 3, characterized in that the material is polyethylene with a bending modulus of 280 MPa or more.
5. The hinge cap according to any one of claims 1 to 3, characterized in that the material is polypropylene with a bending modulus of 500 MPa or more.